This invention relates to antennas, and more particularly, to feed networks for slot antennas in electronic devices.
Due in part to their mobile nature, portable electronic devices are often provided with wireless communications capabilities. Portable electronic devices may use wireless communications to communicate with wireless base stations. For example, cellular telephones may communicate using cellular telephone bands at 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz (e.g., the main Global System for Mobile Communications or GSM cellular telephone bands). Portable electronic devices may also use other types of communications links. For example, portable electronic devices may communicate using the Wi-Fi® (IEEE 802.11) bands at 2.4 GHz and 5.0 GHz and the Bluetooth® band at 2.4 GHz. Communications are also possible in data service bands such as the 3 G data communications band at 2100 MHz band (commonly referred to as UMTS or Universal Mobile Telecommunications System).
To satisfy consumer demand for small form factor wireless devices, manufacturers are continually striving to reduce the size of components that are used in these devices. For example, manufacturers have made attempts to miniaturize the antennas used in portable electronic devices.
A typical antenna may be fabricated by patterning a metal layer on a circuit board substrate or may be formed from a sheet of thin metal using a foil stamping process. These techniques can be used to produce internal antennas that fit within the tight confines of a compact portable device such as a handheld electronic device. With conventional portable electronic devices, however, design compromises are made to accommodate such antennas. These design compromises may include, for example, compromises related to antenna efficiency and antenna bandwidth. It can therefore be difficult to integrate conventional antennas into electrical devices while maintaining satisfactory performance.
It would therefore be desirable to be able to provide improved antenna structures for electronic devices such as portable electronic devices.